In conventional water-based lithography, an aqueous fountain solution if first applied to a planographic plate having a pattern of water repellent areas on a water receptive background whereby the water wets only the hydrophilic areas. Generally the inked image is then transferred to an offset (blanket) roller from which the actual printing takes place. Alternatively the inked image can be transferred directly to the receiver sheet.
Although lithographic printing has been widely recognized and commercialized to a great extent, there have been problems in ink-fountain solution emulsification, and maintaining the required delicate balance between the quantity of ink and fountain solution employed in order to maintain image fidelity and uniformity. An imbalance of the proper ink to water ratio can cause background inking (scumming) if there is insufficient water or insufficient image density (blinding) if excessive water covers the image areas of the plate. It is to these problems to which this invention is directed.